What is a black hole? Do they really exist? How do they form? How are they related
to stars? What would happen if you fell into one? How do you see a black hole if they
emit no light? What’s the difference between a black hole and a really dark star?
Could a particle accelerator create a black hole? Can a black hole also be a worm
hole or a time machine?
In Astro 101: Black Holes, you will explore the concepts behind black holes. Using the theme of black holes, you will learn the basic ideas of astronomy, relativity, and quantum physics.
After completing this course, you will be able to:
• Describe the essential properties of black holes.
• Explain recent black hole research using plain language and appropriate analogies.
• Compare black holes in popular culture to modern physics to distinguish science fact from science fiction.
• Describe the application of fundamental physical concepts including gravity, special and general relativity, and quantum mechanics to reported scientific observations.
• Recognize different types of stars and distinguish which stars can potentially become black holes.
• Differentiate types of black holes and classify each type as observed or theoretical.
• Characterize formation theories associated with each type of black hole.
• Identify different ways of detecting black holes, and appropriate technologies associated with each detection method.
• Summarize the puzzles facing black hole researchers in modern science.

MG

its the Best ever Course and i learned a lot things about which i have not heard before i will strongly recommend this to people who want to know about black holes.

JS

Jun 25, 2019

Filled StarFilled StarFilled StarFilled StarFilled Star

Definitely good introductory course for someone interested in black holes! The instructors are funny and really taught me things with certain detail. Like it!

De la lección

Sizing Up Black Holes

So far discussion has focussed on either the general case for black holes, of the stellar mass variety (endpoint of a star's life). In this module students will explore the various sizes of black holes and their measurable properties. Students will learn that there are four major types of astrophysical black holes (primordial/mini black hole’s, stellar mass, intermediate mass and supermassive black holes), and discover current theories on their formation, and what might feed them. Students will also gain an knowledge of ‘no-hair’ theorem and gravitational lensing. We will also explore the formation of supermassive black holes, intermediate mass black holes, and mini black holes in particle accelerators.

Impartido por:

Sharon Morsink

Associate Professor

Transcripción

Supermassive black holes are the kind that have a million to a billion times the mass of our sun. So, these are the really massive galaxies. We think there's one in the center of pretty much every big galaxy, like the Milky Way and bigger ones and smaller ones. So, supermassive black holes, when they have a lot of stuff when they're growing, when they're actively feeding, and have a lot of stuff flowing in through an accretion disk onto the black hole, and that stuff, as it falls towards the black hole, gets hot, super hot to the point where it emits that really high energies of X-rays and gamma rays. These hot accretion disks are so bright. So, just to say that again, this is mass outside the event horizon so it's still able to let photons out. So, it's bright. It's not stuck inside where the photons can't get out. But it's all this mass that's swirling around the outside of the event horizon of the black hole. It gets so hot and so bright that we can see these objects all the way out to the edges of the observable universe. So, we can see them out at redshifts of seven or eight. This is way back when the universe was really young. We study that radiation from the hot, the heat, and the photons coming off of this material as it tries to flow in towards the black hole. We can see that the mass at the center is already enormous, it's already millions or billions of times the mass of the sun. So, the mystery for supermassive black hole scientists is how did you get something that massive so early on in the life of the universe. It means, you had to get all that mass down into a black hole at very early times. So, one way you can make black holes smaller kinds of you explode stars and the stars collapse back down, and can give you a black hole. But those black holes are only maybe 10 or 30 times the mass of the Sun. So, if you want to build up take building blocks of 30 solar mass things, and build up to a million solar masses or a billion solar masses, you'd need a billion or a million of those objects to crash together in LIGO-like mergers. We don't think that's very likely, that would be a whole lot of stars exploding. We would see all these starbursts all over the edges of the universe. Or you could just force mass in there really fast. But it's basically... It's hard we don't have a good physical model for how you can get so much mass into a black hole so early in the life of the universe. So, that's a mystery I would really love to work on more, to think about the formation of black holes in the very early universe, and then how they evolve as we move toward the present day. We're only now just getting a new generation of space telescopes that can allow us to probe black hole growth, way at those very early times. It's hard work. It's very finicky, the galaxies they live in are small and sometimes this bright hot gas around the black hole, just sort of out shines everything else. It's really hard to see the environment, and to understand what the building blocks were that gave you that supermassive thing just really fast. They basically grew really fast, and we don't know how they could possibly grow that fast.